Sewing machine and computer readable medium storing sewing needle status evaluation program

ABSTRACT

A sewing machine provided with a needle bar having a sewing needle interchangeably attached to its lower end including an imaging element that captures images of the sewing needle; an extractor that extracts a shape of the sewing needle from the images of the sewing needle captured by the imaging element; an abnormality determiner that determines presence/absence of abnormalities in measurements of the sewing needle based on the shape of the sewing needle extracted by the extractor; and an abnormality alerter that alerts the presence of abnormalities determined by the determiner.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromthe prior Japanese Patent Application 2008-033212, filed on Feb. 14,2008, the entire contents of which are incorporated herein by reference.

FIELD

The present disclosure relates to a sewing machine allowinginterchangeable attachment of sewing needle on a lower end of a needlebar. The present disclosure also relates to a computer readable mediumstoring a needle status evaluation program for use in such sewingmachine.

BACKGROUND

A sewing machine in general is provided with a needle bar to which asewing needle is detachably attached interchangeably to its lower end.Such detachable configuration allows the sewing needle to be replacedwhen the user encounters sewing needle wears during the sewing operationsuch as bending, broken tip, and rounded tip. Such detachableconfiguration also allows the user to selectively attach a desiredsewing needle most suitable in thickness, for example, for sewingdifferent types and thickness of workpiece cloth. In view of such modeof usage sewing machine generally comes with an accessory of replacementsewing needles of various thickness.

The timing in which the sewing needle replacement is made relies on userjudgment based on visual recognition. Subtle bends or rounding of needletip, however, is likely to be overlooked by the user if visualrecognition is the only resort in making the judgment.

To address such issue, JP H11-221392 A discloses a needle breakagedetector that automatically detects sewing needle breakage. Thedisclosed needle breakage detector comprises a proximity sensor fordetecting the tip of the sewing needle at its lowermost point ofvertical reciprocation. The sewing operation is immediately stopped assoon as needle breakage has been detected.

Though the above described needle breakage detector is capable ofdetecting needle breakages, detection of other wear (deterioration) suchas bending and rounded tip are not guaranteed. Thus, it still rests uponuser's visual recognition for detection of such wears. Another problemwith the conventional needle breakage detector was its installation.Since the detector (proximity sensor) required installation at thelowermost point of needle reciprocation residing below the needle plate,where components such as rotary shuttle, feed dog drive mechanism, andthread cutting mechanism were installed, it was difficult to secureappropriate spacing for installation of the detector.

Another general problem encountered under the conventional sewingoperation using the above described detector was inappropriate selectionof a sewing needle for sewing a given type of workpiece cloth. Forinstance, if the user fails to select a sewing needle of appropriatethickness for workpiece cloth of different thickness and type, it maycause the sewing needle to bend or leave an oversized through hole onthe workpiece cloth consequently impairing the look and quality of theresulting stitches. Further, an embroiderable sewing machine requires asewing needle of a predetermined thickness when embroidering amultiplicity of stitches in order to obtain a descent embroiderypattern. The conventional detector, however, lacks in the capacity ofdetermining whether or not the thickness of a given sewing needle isappropriate for the thickness and the type of workpiece cloth to besewn.

SUMMARY

An object of the present disclosure is to provide a sewing machine thatallows automatic evaluation of sewing needle wear without relying onuser's visual recognition and decision to prevent malfunctioning causedby worn out sewing needles. Another object of the present disclosure isto provide a sewing machine that is capable of automatically determiningwhether or not a sewing needle of appropriate thickness has beenattached for sewing a workpiece cloth of a given thickness or type andfor executing embroidering sewing. Yet, another object of the presentdisclosure is to provide a computer readable medium that stores a sewingneedle status evaluation program for realizing the above describedfeatures.

In one aspect, a sewing machine provided with a needle bar having asewing needle interchangeably attached to its lower end includes animaging element that captures images of the sewing needle; an extractorthat extracts a shape of the sewing needle from the images of the sewingneedle captured by the imaging element; a determiner that determinespresence/absence of abnormalities in measurements of the sewing needlebased on the shape of the sewing needle extracted by the extractor; andan alerter that alerts the presence of abnormalities determined by thedeterminer.

According to the above described configuration, the shape of sewingneedle is extracted by the extractor from the image data of sewingneedle captured by the imaging element and presence/absence ofabnormalities in the sewing needle is determined by the determinerthrough evaluation of various measurements of the sewing needle. Byverifying whether or not measurements such as the length of the sewingneedle, widths of various portions of the sewing needle, and thedistance between the center line and the edge of the sewing needle atvarious heights of the sewing needle is within a predetermined thresholdrange from the regular measurements of a brand new sewing needle,presence/absence of abnormalities that require replacement such asbending of sewing needle and broken tip and rounded tip can bedetermined. If determined that sewing needle is abnormal, an alert isissued to that effect by the alerter so that the user is promptlyinformed of the abnormalities of the sewing needle to prevent anytrouble caused by unattended abnormalities.

In another aspect, a sewing machine provided with a needle bar having asewing needle interchangeably attached to its lower end includes animaging element that captures images of the sewing needle; an extractorthat extracts a shape of the sewing needle from the images of the sewingneedle captured by the imaging element; a storage that pre-stores aninitial shape of the sewing needle; an abnormality determiner thatdetermines presence/absence of abnormalities in the shape of the sewingneedle extracted by the extractor by comparing with the initial shapepre-stored in the storage; and an alerter that alerts the presence ofabnormalities determined by the determiner.

According to the above described configuration, images of the sewingneedle captured by the imaging element is extracted by the extractor forcomparison with the initially extracted shape data stored in the storageto determine the absence/presence abnormalities in the sewing needle bythe determiner. By comparing the extracted shape and the pre-storedshape of the sewing needle to detect the difference in measurements ofvarious portions of the sewing needle and verifying whether thedifference is within a predetermined threshold range, absence/presenceof abnormalities that require sewing needle replacement such as bending,tip rounding, and tip breakage can be determined. If abnormalities arefound, an alert is issued to that effect by the alerter so that the useris promptly informed of the abnormalities of the sewing needle toprevent any trouble caused by unattended abnormalities.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, features and advantages of the present disclosure willbecome clear upon reviewing the following description of theillustrative aspects with reference to the accompanying drawings, inwhich,

FIG. 1 depicts a first exemplary embodiment of a sewing machineaccording to the present disclosure and provides a perspective view ofthe sewing machine;

FIG. 2 is a front view of the sewing machine with an embroidery machineattached;

FIG. 3 is an enlarged perspective view of a sewing needle;

FIG. 4 is a block diagram indicating an electrical configuration of thesewing machine;

FIG. 5A is a front view of the sewing needle;

FIG. 5B is an enlarged front view of the tip of the sewing needlemaintaining its initial state;

FIG. 5C is an enlarged front view of the tip of the sewing needle haltedat a leftwardly inclined position;

FIG. 5D is an enlarged front view of the tip of the sewing needle with arounded tip caused by frictional wear;

FIG. 6A depicts a shape of the sewing needle free of bend;

FIG. 6B depicts a shape of the sewing needle halted at a leftwardlyinclined position;

FIG. 6C depicts a shape of the sewing needle having a bend;

FIG. 7 indicates a flowchart describing an overall control flow ofabnormality evaluation of sewing needle executed by a controller;

FIG. 8 is a flowchart elaborating step S3 of FIG. 7;

FIG. 9A depicts a second exemplary embodiment of the present disclosureand provides a front view of the sewing needle;

FIG. 9B provides an exemplary mapping of sewing needle thickness withsewing needle number;

FIG. 10 indicates a flowchart describing an overall control flow ofneedle thickness evaluation executed by the controller;

FIG. 11 elaborates step S21 of FIG. 10;

FIG. 12 elaborates step S23 of FIG. 10;

FIG. 13 elaborates step S25 of FIG. 10;

FIG. 14 depicts a third exemplary embodiment of the present disclosureand corresponds to FIG. 7; and

FIG. 15 elaborates step S44 of FIG. 14.

DETAILED DESCRIPTION

One exemplary embodiment of the present disclosure will be describedwith reference to FIGS. 1 to 8.

FIGS. 1 and 2 provide perspective views of the overall configuration ofa sewing machine (household electronic sewing machine) in accordancewith the present disclosure. FIG. 1 shows the sewing machine with atable attachment on its sewing machine bed for utility stitching andFIG. 2 shows the sewing machine with an embroidery machine attachment onits sewing machine bed for embroidering.

The main body of sewing machine 1 is provided integrally with alaterally (X-direction) extending sewing machine bed 2, an upwardlyextending pillar 3 standing on the right end of sewing machine bed 2,and an arm 4 extending leftward over sewing machine bed 2 from the upperend of pillar 3. The extreme end of arm 4 constitutes a head 5. At theupper portion of arm 4, a cover 4 a is provided for opening and closingaccess into the arm 4. Though not shown, arm 4 includes a compartmentfor storing a needle thread spool. For ease of explanation to follow,the direction to which the user positions him/herself relative to sewingmachine 1 is the front side, and the opposing direction, naturally isthe rear side. The direction toward which pillar 3 is displaced from thecenter of arm 4 is the right side and the opposing direction, naturally,is the left side.

As can be seen in FIG. 3, head 5 provided at the end of arm 4 has aneedle bar 6 configured vertically movably and laterally (X-direction)swingably. At the lower end of needle bar 6, a sewing needle is attachedby way of needle clamp 8 as can be seen in FIG. 5A. As known in the art,a fastening screw 9 is provided at the right end of needle clamp 8 toallow attachment/detachment (replacement) of sewing needle 7 by turningfastening screw 9. Sewing needle 7 may be subject to wears(deterioration) such as bend, broken tip, and rounded tip over time anduse, which requires replacement of sewing needle 7 by the user.

Provided at the lower potion of needle bar 6 (sewing needle 7) extendingfrom head 5, is a presser foot 10. At the left side of needle bar 6(sewing needle 7) a needle threader (not shown) known in the art isprovided for threading a needle thread drawn from a thread spool to aneedle eye (not shown).

Though not explained in detail, arm 4 contains a sewing machine mainshaft rotated by a sewing machine motor 12 (refer to FIG. 4). Arm 4further contains a needle-bar drive mechanism driven by the sewingmachine main shaft to vertically move needle bar 6, and a needle-barswing mechanism driven by a needle-swing pulse motor 13 (refer to FIG.4) to laterally (X-direction) swing needle bar 6. Arm 4 further containscomponents such as a thread take-up drive mechanism that verticallymoves a thread take-up (not shown) in synchronism with the verticalmovement of needle bar 6, and a thread tension regulator that adjuststhread tension.

Though not shown in detail, the sewing machine main shaft is providedwith a sectoral shutter (blocking plate) rotating integrally with themain shaft. The rotational status of the shutter is detected opticallyby a photo-interrupter provided at a sewing machine frame. The shutterand the photo-interrupter constitute a main shaft angle detector 14(refer to FIG. 4). The vertical positioning of needle bar 6 driven bythe main shaft can be sensed by the angle of the main shaft detected bymain shaft angle detector 14. Needle bar 6 is configured to stop at itslifted position (substantially the uppermost position of the verticalreciprocation) when the sewing operation is stopped by operation of thelater described start/stop key 15 a.

As can be seen in FIGS. 1 and 2, key switches 15 are provided on thefront face of arm 4 for user operation. Though not explained in detail,key switches 15 comprise controls such as start/stop switch 15 a thatinstructs start/stop of a sewing operation, a back stitch key, needlepositioning key, thread cutting key, and a speed adjustment dial. On thefront face of pillar 3, a vertically elongate liquid crystal display 20(hereinafter simply referred as LCD 20) is provided for displayingvarious information in full color.

LCD 20 displays information such as various utility and embroiderypatterns, names of various functions required in the sewing operation,and various informational messages. Selection of patterns and executionof functions are carried out through a touch panel 21 (refer to FIG. 4)provided on the surface of LCD 20. LCD 20 displays error messages(alert) when abnormality is found at sewing needle 7.

Referring to FIG. 1, a needle plate 16 is provided on the upper surfacesewing machine bed 2. Though not shown, within sewing machine bed 2situated below needle plate 16, are components such as a feed dog drivemechanism that drives a feed dog in synchronism with the verticalmovement of needle bar 6, a full rotary shuttle containing a bobbinthread bobbin and forming stitches in cooperation with sewing needle 7,and a needle cutting mechanism that cuts the needle thread and bobbinthread. As can be seen in FIG. 1, a utility sewing table 24 isattachably/detachably attached to the left front portion of sewingmachine bed 2. Utility sewing table 24 is used for sewing utilitypatterns on workpiece cloth (not shown) fed by the feed dog.

Referring to FIG. 2, a well known embroidery machine (embroidery frametransfer mechanism) may be attachably/detachably attached to the leftfront portion of sewing machine bed 2 instead of utility sewing table24. Embroidery machine 22 is attachably/detachably attached with anembroidery frame (not shown) that holds the workpiece cloth (not shown).Embroidery machine 22 comprises an embroidery frame transfer mechanism(not shown) an X-directional motor (not shown) and a Y-directional motor(not shown). The embroidery frame transfer mechanism transfers theembroidery frame freely in the X-direction (lateral) and the Y-direction(longitudinal) orthogonal to the X-direction in the space overlyingsewing machine bed 2 (needle plate 16) and is driven by the X-directionmotor and the Y-direction motor. When embroidery machine 22 is attachedto sewing machine bed 2, embroidery machine 22 and consequentlyX-directional and Y-directional motors are electrically connected to alater described controller 25 of the sewing machine through a connector23 (refer to FIG. 4) provided at sewing machine bed 2. The attachment ofembroidery machine 22 triggers automatic mode switching from utilitysewing mode to embroidery sewing mode.

Referring now to FIG. 3, at the lower front end portion of head 5, whichis, when viewed from sewing needle 7, a portion located forwardly andrightwardly upward relative to sewing needle 7, a first image sensor 17is provided for capturing images of sewing needle 7. Referring back toFIG. 1, a second image sensor 18 is provided on the rear portion of thepillar 3 left wall facing the sewing needle 7 for capturing images ofsewing needle 7. In the present exemplary embodiment, first and secondimage sensors 17 and 18 comprise a compact imaging device such as a CMOS(Complementary Metal Oxide Semiconductor) imaging device.

Sewing needle 7 and consequently needle bar 6 are halted at the liftedposition elevated from needle plate 16 when the sewing operation isstopped. First and second image sensors 17 and 18 are located so thatimages of sewing needle 7 halted at the lifted position can be capturedfrom different locations (angles).

Utility sewing involves different styles of stitching such as straightstitching and zigzag stitching. Zigzag stitching is carried out whilelaterally swinging needle bar 6 (sewing needle 7) by the needle-barswing mechanism. Straight stitching is basically carried out at acentral baseline with the center line of needle bar 6 (sewing needle 7)being orthogonal to the upper surface of needle plate 16. Straightstitching, however, may be carried out at a left baseline with needlebar 6 (sewing needle 7) leftwardly inclined or at a right baseline withneedle bar 6 (sewing needle 7) rightwardly inclined. In such cases, asdepicted somewhat exaggerated in FIG. 5C and FIG. 6B, needle bar 6(sewing needle 7) is halted at a leftwardly swung (inclined) positionaccording to a present swing width, and rightwardly swung (inclined)position for example. Angle of sewing needle 7 (angle of incline ofsewing needle 7 relative to the center baseline) in this case, is set toa predetermined value obtained from the angular data that corresponds toa preset swing width.

As can be seen in FIG. 4, image data captured by first and second imagesensors 17 and 18 respectively is inputted into image processing circuit19. Though not described in detail, image processing circuit 19transforms the perspective of the image captured by first image sensor17 from the upper front view of sewing needle 7 into an image thatsubstantially appears to be taken from the front side of sewing needle7. At the same time, known image processing such as binarization andoutline (edge) extraction are performed to extract the shape of sewingneedle 7. Similarly, image processing circuit 19 performs binarizationand outline (edge) extraction of the image captured by second imagesensor 18 from the right side and rear side surface view of sewingneedle 7. The extracted shape of sewing needle 7 by image processingcircuit 19 is taken as input into controller 25 as shape data.

FIG. 4 briefly describes an electrical configuration of the sewingmachine according to the present exemplary embodiment. Controller 25 isconfigured primarily by a microcomputer comprising components such as aCPU 26, a ROM 27, a RAM 28, and an EEPROM 29. ROM 27 stores variousitems such as a control program for controlling the sewing operation, aneedle status evaluation program, stitch data required for the sewingoperation, and various data required for verification of later describedabnormalities of sewing needle 7. As will be described afterwards,needle evaluation program automatically evaluates wear of sewing needle7. The needle status evaluation program may be executed by way of anexternal storage medium such as an optical disc, magnetic disc, andcompact card or stick memory.

Controller 25 is connected to various keys switches 15 includingstart/stop switch 15 a, and to touch panel 21 for receiving theiroperation signals. Controller 25 further establishes connection withmain shaft angle detector 14 to receive its detection signal. Asdescribed earlier, controller 25 is connected to image processingcircuit 19 for controlling image sensors 17 and 18 and for receiving theshape data of sewing needle 7 from image processing circuit 19.

Controller 25 is further connected to drive circuits 30, 31, and 32 forcontrolling LCD 20, sewing machine motor 12 and needle-swing pulse motor13 to execute the sewing operation. A buzzer 34 for alerting purposes isfurther connected to controller 25 through drive circuit 33. Theaforementioned connector 23 is also connected to controller 25.

As will be described through description of the operation of the abovedescribed configuration with reference to a flowchart, the softwareconfiguration, more specifically, the execution of needle statusevaluation program of controller 25 provides automatic detection(evaluation) of presence of wear or deterioration such as bending,broken tip, and rounded tip of sewing needle 7.

Controller 25 captures images of sewing needle 7 at predetermined timingthrough image sensors 17 and 18 and extracts the shape data of thesewing needle 7 from the captured image by image processing circuit 19.Controller 25 obtains measurements of various portions of sewing needle7 based on the shape data of sewing needle 7 and determines if any ofthe measurements are abnormal. Controller 25, when encountering anabnormality, displays a message on LCD 20 indicating to that effect witha ringing of buzzer 34.

To describe more specifically on abnormality evaluation, controller 25determines occurrence of deformation of sewing needle 7 based onevaluation of the degree of bend in view of the overall shape of sewingneedle 7; where as occurrence of rounded tip and broken tip isdetermined based on evaluation of the shape or the sharpness of the tipof sewing needle 7.

The operation of the above described configuration will be describedhereinafter with reference to FIGS. 5A to 8. Flowchart given in FIG. 7indicates the overall process flow of abnormality evaluation of sewingneedle 7 executed by controller 25. Flowchart given in FIG. 8 elaboratessteps S3 of flowchart given in FIG. 7. In the present exemplaryembodiment, abnormality evaluation of sewing needle 7 is executed everytime power of sewing machine 1 is turned on. The evaluation is furtherexecuted periodically, when cumulative sew time has exceeded apredetermined time interval of 10 hours, for example, or when cumulativestitch count has exceeded a predetermined stitch count of 10 thousandstitches, for example.

At step S1 of FIG. 7, images of sewing needle 74 attached to needle bar6 is captured through image sensors 17 and 18 to obtain image data ofsewing needle 7. Then, at step S2, image processing circuit 19 extracts(recognizes) the outline (shape) of sewing needle 7 from the obtainedimage data of sewing needle 7. Then, at step S3, sharpness and bendingof the tip of sewing needle 7 is evaluated based on various measurementsof sewing needle 7 measured from the extracted shape of sewing needle 7.

Flowchart given in FIG. 8 elaborates step S3. At step S11, the lowermostpoint of the extracted shape of sewing needle 7 is recognized as the tipof sewing needle 7. Then, at step S12, controller 25 looks up the datarepresenting the angle of incline of sewing needle 7 based on thespecified pattern (stitch type) and swing width. Based on the obtainedangle of sewing needle 7, a corresponding preset center line O (refer toFIGS. 5B to 5D and FIGS. 6A to 6C) of sewing needle 7 is assumed.

FIG. 5A shows a bottom end of needle bar 6 and sewing needle 7 and FIGS.5B to 5D provide an enlarged view of the shape of sewing needle 7 tiprepresented by reference symbol E at FIG. 5A. FIGS. 5B and 5D showsewing needle 7 stopped in a straight position with no incline (centerbaseline), and FIG. 5C shows sewing needle 7 stopped at incline θ to theleft side of sewing needle 7 (left baseline). In the example shown inFIGS. 5B and 5D, center line O can be drawn that extends vertically fromthe tip of sewing needle 7 to the upper surface of needle plate 16. Inthe example shown in FIG. 5C, center line O inclined by angle θ can bedrawn that extends from the tip of sewing needle 7. FIGS. 5B and 5Cdepicts the tip of sewing needle 7 maintaining its initial sharpness,and FIG. 5D depicts slight rounding observed at the tip of sewing needle7 by wear.

At step S13, a determination is made as to whether or not width “b” ofsewing needle 7 at height “a” (1 mm, for example) from the tip of sewingneedle 7 is equal to or less than a predetermined value (0.5 mm, forexample). If sewing needle 7 is inclined as depicted in FIG. 5C, width“b” can be obtained by plotting a point which resides on center line Oand which is distanced by length “a” from the tip of sewing needle 7 anddrawing a line which passes through the plotted point which is furtherorthogonal to center line O. The width of sewing needle 7 superimposedon the drawn line provides the required width “b”. The tip of sewingneedle 7 is profiled such that the tip (lower end) has the least widthand the width increases with distance from the tip. Thus, as the tip ofsewing needle 7 wears and is rounded to some extent, width “b” of sewingneedle 7 at height “a” from the tip of sewing needle 7 exceeds apredetermined value of 0.7 mm, for example, at some point in time as canbe seen in FIG. 5D. The same is true if the tip of sewing needle isbroken off.

The above described process at step S13 allows detection of rounded orbroken tip of sewing needle 7. If width “b” of sewing needle 7 at height“a” from the tip of sewing needle 7 is determined to be equal to or lessthan a predetermined value (step S13: Yes), a determination that no tiprounding or tip breakage has occurred at the tip of sewing needle 7 andthe control proceeds to step S15. As opposed to this, if width “b” ofsewing needle 7 at height “a” from the tip of sewing needle 7 isdetermined to exceed the predetermined value (step S13: No), it isdetermined that tip rounding or tip breakage has occurred. Then at thefollowing step S14, an alert is issued to notify a rounded tip or brokentip to prompt replacement of sewing needle 7. The alert is notified tothe user through a message displayed on LCD 20 and a ringing of buzzer34.

If no rounded tip or broken tip is encountered (step S13: Yes),determination is made at step S15 as to whether or not bending of sewingneedle 7 has occurred by evaluating the overall shape of sewing needle7. The occurrence of bend is determined through a process specificallydescribed in FIGS. 6A to 6C. After shape (outline) extraction of sewingneedle 7, multiple height measurements (3 in FIGS. 6A to 6C) is markedat predetermined spacing c (5 mm, for example) throughout the extent ofsew needle 7 running from the tip to the base end. Then, lengths (X1 toX6 in FIGS. 6A to 6C) from center line O to the left and right edges ofsewing needle 7 is measured to verify its symmetry, in other words, toverify that center line O passes through the center of sewing needle 7.

FIGS. 6A and 6B depict sewing needle 7 which is free of bend. FIG. 6Bdepicts sewing needle 7 halted with incline θ to the left side of sewingneedle 7 (left baseline) and FIG. 6C provides an exaggerated depictionof a bent sewing needle 7. If sewing needle 7 is straight and is bendfree, relation between widths X1 to X6 can be described as X1=X2, X3=X4,and X5=X6 as indicated in FIGS. 6A and 6B. If the above relation istrue, a determination is made that sewing needle 7 is bend free (stepS15: Yes) to terminate the control.

As opposed to this, if bend is observed in sewing needle 7 as can beseen in FIG. 6C, X1=X2, X3=X4, and X5=X6 are not met, and hence adetermination is made that sewing needle is bent (step S15: No). Then,in the following step S16, an alert is issued to indicate a bend andprompt replacement of sewing needle 7. The alert is, as describedearlier, notified to the user through a message displayed on LCD 20 anda ringing of buzzer 34.

The above described configuration automatically detects occurrence ofsewing needle 7 abnormalities and noticeably alert the user that sewingneedle 7 has suffered substantial wear that would require replacement.By seeing and hearing the alert, the user is given an opportunity toreplace sewing needle 7 at an appropriate timing. Though not shown inFIG. 8, if abnormality is found in sewing needle 7, meaning that Nodetermination is made at step S13 or step S15, controller 25 mayprohibit start up of sewing machine motor 12. In such case, execution ofsewing operation is allowed only after replacement of sewing needle 7and after being verified that no abnormality is found throughre-evaluation of sewing needle 7.

According to the above described exemplary embodiment, the shape ofsewing needle 7 is extracted from the image data of sewing needle 7captured by image sensors 17 and 18 and presence/absence ofabnormalities in sewing needle 7 can be readily and reliably determinedthrough evaluation of various measurements of sewing needle 7. Morespecifically, by evaluating the overall shape of sewing needle 7,presence/absence of bend in sewing needle 7 can be determined readilyand reliably. Similarly by evaluating the shape of the tip of sewingneedle 7, presence/absence of rounded tip or broken tip can bedetermined readily and reliably. If abnormalities are encountered, anoticeable alert is brought to user attention promptly through displayon LCD 20 and ringing of buzzer.

Thus, as opposed to the conventional detector relying on the user indetermining the need of sewing needle 7 replacement, the presentdisclosure provides automatic evaluation of the wear of sewing needle 7without relying on visual recognition and decision by the user.Replacing sewing needle 7 in an appropriate time frame provides afavorable result of preventing trouble caused by a damaged sewing needle7.

Further, since the present exemplary embodiment obtains multiple imagedata, the shape of sewing needle 7 can be extracted with greateraccuracy. Especially when compared to images being captured from asingle direction only, the present exemplary embodiment advantageouslyallows precise evaluation of bends occurring in various directions.

Image sensors 17 and 18 configured by CMOS (Complimentary Metal OxideSemiconductor) or CCD (Charged Couple Device) are provided at 2different locations of sewing machine 1 to allow compact and low costimplementation on sewing machine 1 and consequently keeping sewingmachine 1 compact.

A second exemplary embodiment will be described with reference to FIGS.9A to 13. Hardware configurations that are identical to the firstembodiment will be represented by identical reference symbols and willnot be shown or described in detail. The description will be givenhereinafter on portions that differ from the first exemplary embodiment.

A sewing machine according to the second exemplary embodiment, as shownin FIG. 9A, comes with accessory of replacement needles of differentthickness types (4, in the present exemplary embodiment) for selectiveattachment by the user. FIG. 9B is a chart showing thickness (width) Aof sewing needles 7 identified by needle number. The thickness A ismeasured at 10 mm, for example, from the tip of sewing needle 7 as shownin FIG. 9B. In the present exemplary embodiment, 4 types of sewingneedles 7 identified as needle numbers (needle no.) 9, 11, 14, 16 areprovided which increase in thickness with needle number.

The 4 types of sewing needles 7 may be selectively used based on thetype or thickness of the workpiece cloth when forming utility stitches.More specifically, needle no. 14 is used for “normal” cloth, needle no.16 for “thick” cloth, needle no. 11 for “thin” cloth, and needle no. 9for “extra thin” cloth.

Types of workpiece cloth categorized as “normal” may be: broadcloth,tafta, flannel, and gabardine; “thick” may be: denim, corduroy, andtweed; and “thin” may be: lawn, georgette, and polar. It is recommendedto sew above types of cloth with appropriate type of sewing needle asexemplified above.

Embroidering, especially when using embroidery machine 22, involvesmultiplicity of stitches, and since embroidering in general is carriedout on a single piece of cloth, it is desirable to use a thin needle, inthis case, needle no. 11.

When sewing needle 7 of appropriate thickness is not used in sewingspecific types or thickness of workpiece cloth, sewing needle 7 may bendor leave an oversized through hole that would impair the look of thefinished product.

The present exemplary embodiment, being a modification of the firstexemplary embodiment, primarily utilizes its software configuration(execution of needle status evaluation program) to extract the shapedata of sewing needle 7 through image processing circuit 19 based onimages of sewing needle 7 captured through image sensors 17 and 18.Then, based on the shape data of sewing needle 7, various measurementsof sewing needle 7 are obtained and evaluated to determine thepresence/absence of wears (deterioration) such as overall bending ofsewing needle and rounded tip or broken tip that are, if found, broughtto user attention.

Further, the software configuration of controller 25 detects thethickness and the type (needle no.) of sewing needle 7 attached, fromthe shape data of sewing needle 7. When in embroidery sewing mode, thatis, when attachment of embroidery machine 22 through connector 23 isdetected, controller determines whether or not the detected thickness ofsewing needle 7 (needle no.) is appropriate (needle no. 11). If thedetected sewing needle 7 is not appropriate, replacement of sewingneedle 7 is prompted through an alert displayed on LCD 20 and ringing ofbuzzer 34.

Utility stitching in the present exemplary embodiment is carried out byselecting the desired utility pattern displayed on LCD 20 through useroperation of touch panel 21 and selection of cloth thickness from thechoice of “normal”, “thin”, and “thick” by depressing the correspondingselection key displayed on LCD 20 through touch panel 21.

Then, controller 25 determines whether or not the specified cloththickness in the utility sewing mode and the detected thickness (needleno.) of sewing needle 7 are appropriate. If determined to beinappropriate, an alert is issued through display on LCD 20 and ringingof buzzer 34 to prompt replacement of sewing needle 7. Instead ofspecifying the thickness of the workpiece cloth, the user mayalternatively be allowed to select the appropriate type of fabric ofworkpiece cloth from the exemplary types of fabric described earlier.

Flowchart given in FIG. 10 indicates the overall process flow ofabnormality evaluation and thickness detection of sewing needle 7executed by controller 25. Flowcharts given in FIG. 11 elaborates stepS21 of FIG. 10 flowchart; FIG. 12 elaborates step S23 of FIG. 10flowchart; and FIG. 13 elaborates step S25 of FIG. 10 flowchart.

That is, the process flows in the same way as in the first exemplaryembodiment in which at step S1 of FIG. 10, controller 25 captures imagesof sewing needle 7 attached to needle bar 6 through image sensors 17 and18 to obtain image data of sewing needle 7. Then, at step S2, imageprocessing circuit 19 extracts (recognizes) the outline (shape) ofsewing needle 7 from the obtained image data of sewing needle 7. Then,at step S3, sharpness and bending of the tip of sewing needle 7 isevaluated based on various measurements of sewing needle 7 measured fromthe extracted shape of sewing needle 7.

Then, at step S21, thickness (needle no.) of sewing needle 7 is detectedfrom the shape data of sewing needle 7 extracted at step S2. The processis describe more specifically in FIG. 11, in which at step S31,thickness “A” is measured at 10 mm, for example, from the tip of sewingneedle 7 as can be seen in FIG. 9A. Then, at step S32, thickness “A” iscompared with preset thickness as exemplified in FIG. 9B and the needleno. that matches or that is in closest distance within a predeterminedrange from thickness A is obtained and displayed on LCD 20.

After obtaining the thickness (needle no.) of sewing needle 7 in theabove described manner, the process returns to FIG. 10. At step S22, adetermination is made as to whether or not the selected sewing mode isthe embroidery sewing mode through detection of attachment of embroiderymachine 22, where attachment of embroidery machine 22 indicates theembroidery sewing mode and if otherwise, the utility sewing mode. If inthe embroidery sewing mode (step S22: Yes), the control proceeds tosteps S23 to execute detection of sewing needle 7 under the embroiderysewing mode.

More specifically, at step S33 of FIG. 12, a determination is made as towhether or not the needle no. obtained at steps S21 (S32) is sewingneedle 7 represented as needle no. 11 which is suitable forembroidering. If attachment of needle no. 11 is verified (step S33:Yes), the control is returned (terminated). If needle no. 11 is notattached (step S33: No), replacement of sewing needle 7 is promptedthrough an alert displayed on LCD 20 and ringing of buzzer 34.

Control is then, returned to FIG. 10 and if the current sewing mode isnot the embroidery sewing mode, but is the utility sewing mode (stepS22: No), a determination is made as to whether or not to executeutility sewing mode. If utility sewing is to be executed (step S24:Yes), the control proceeds to step S25 to execute detection of sewingneedle under the utility sewing mode and if not (step S24: No), thecontrol is terminated.

At step S25, detection of sewing needle 7 in the utility sewing mode iscarried out by specifying the thickness of workpiece cloth from theselection of “normal”, “thin”, and “thick” through user operation oftouch panel 21 at step S35 indicated in FIG. 13. As mentioned earlier,the user may alternatively be allowed select the appropriate type offabric of workpiece cloth from the exemplary types of fabric throughoperation of touch panel 21. Then at step S36, a determination is madeas to whether or not the needle no. of the attached sewing needle 7selected at step S21 (S32) is appropriate for sewing the selectedthickness of workpiece cloth.

As mentioned earlier, needle no. 11 or 9 is appropriate for “thin”cloth, needle no. 14 for “normal” cloth, and needle no. 16 for “thick”cloth. If the detected sewing needle 7 is not appropriate (step S36:No), replacement of sewing needle 7 is prompted through an alertdisplayed on LCD 20 and ringing of buzzer 34. If the detected sewingneedle 7 is appropriate (step S36: Yes), the control is terminated.

According to the above described second exemplary embodiment, wear ofsewing needle 7 is automatically evaluated without relying on visualrecognition and decision of the user and thus prevents negative impacton the sewing operation originating from the deterioration of sewingneedle 7. Further, since an alert is issued to replace sewing needle 7when the thickness of the selected sewing needle 7 for use in theembroidery sewing mode is not appropriate for embroidery sewingoperation, the risk of executing an embroidery sewing operation with aninappropriate sewing needle 7 thickness can be eliminated. The alert toprompt replacement of sewing needle 7 is issued when the thickness ofsewing needle 7 is inappropriate for sewing the specified thickness ofthe workpiece cloth in utility sewing mode as well. Thus, the risk ofexecuting a utility sewing operation with an inappropriate sewing needle7 thickness can likewise be eliminated. The above configuration providesimproved quality of the sewing operation.

FIGS. 14 and 15 indicate a third exemplary embodiment of the presentdisclosure, which differs from the first exemplary embodiment in thefollowing respects. In the third exemplary embodiment, when starting theuse of sewing needle 7, in other words, when sewing needle 7 is attachedto needle bar 6 for the very first time, the image of sewing needle 7 iscaptured by image sensors 17 and 18. Then, the shape of sewing needle 7is extracted based on the captured image data and the initiallyextracted shape data (initial shape data) is stored (registered) inmemory (EEPROM 29) of controller 25.

Then, after starting the use of sewing needle 7, controller 25 capturesimages of sewing needle 7 by image sensors 17 and 18 at predeterminedtimings and extracts the shape data of sewing needle 7 from the capturedimages through image processing circuit 19. By comparing the shape dataof sewing needle 7 with the initially extracted shape data stored in thememory of controller 25, absence/presence of bend in sewing needle 7,rounded tip, and broken tip is determined. If abnormalities are found,an alert is issued to that effect through display on LCD 20 and ringingof buzzer 34.

Flowchart given in FIG. 14 indicates the entire process flow ofabnormality evaluation of sewing needle 7 executed by controller 25, andstep S44 of the process flow is elaborated in FIG. 15. In step S41 ofFIG. 14, the image of sewing needle 7 is captured by image sensors 17and 18 from which the shape of sewing needle 7 is extracted by thecaptured image data and the initially extracted shape data is stored(registered) in memory of controller 25 as described earlier.

Then, at step S42, the image data of sewing needle 7 attached to needlebar 6 is captured by image sensors 17 and 18 after starting the use ofthe newly attached sewing needle 7. At step S43, the shape (outline) ofsewing needle 7 is extracted (recognized) from the captured imagesthrough image processing circuit 19. At step S44, the extracted shapedata of sewing needle 7 is compared with the initially extracted shapedata of sewing needle 7 stored in the memory of controller 25 toevaluate the tip sharpness and tip bending of sewing needle 7.

More specifically, at step S51 of FIG. 15, the initially extracted shapedata of the newly attached sewing needle 7 is compared with the currentshape data of sewing needle 7 to verify whether the two data match (toverify whether the two data fall within a predetermined similaritythreshold). If determined to be in conformity (step S51: Yes) thecontrol is terminated since no abnormality is observed in sewing needle7. If determined data do not match (step S51: No), a determination ismade at step S52 as to whether or not the portion of sewing needle 7failing to match the original status involves only the measurement inthe height from the tip of sewing needle 7.

If the un-matching portion consists only of the height from the tip ofsewing needle 7 (step S52: Yes), it can be determined that theabnormality comprises either a rounded tip or a broken tip. Thus, atstep S53, an alert is issued to inform the user of a rounded tip orbroken tip through a message displayed on LCD 20 and ringing of buzzer34 to prompt replacement of sewing needle 7. If the un-matching portiondoes not consist only of the height from the tip of sewing needle 7(step S52: No), the abnormality may be a bend or breakage. Thus, at stepS54, an alert is issued to inform the user of a needle bend or needlebreakage through a message displayed on LCD 20 and ringing of buzzer 34to prompt replacement of sewing needle 7.

The above described third exemplary embodiment also extracts the shapedata of sewing needle 7 from the image data of sewing needle 7 capturedby image sensors 17 and 18 and compares the shape data with theinitially extracted shape data of sewing needle 7 to readily andreliably determine the presence/absence of abnormalities in sewingneedle 7. When an abnormality is encountered, the user is promptly andnoticeably alerted through display on LCD 20 and ringing of buzzer 34.

Thus the third exemplary embodiment provides the favorable effectsprovided by the first exemplary embodiment. That is, as opposed to theconventional detector relying on the user in determining the need ofsewing needle 7 replacement, the third exemplary embodiment alsoprovides automatic evaluation of the wear of sewing needle 7 withoutrelying on visual recognition and decision by the user. Replacing sewingneedle 7 in an appropriate time frame, provides a favorable result ofpreventing trouble caused by wears of sewing needle 7.

The above described exemplary embodiments may be partially modified asfollows.

The two image sensors 17 and 18 provided in the above describedembodiments for capturing images of sewing needle 7 may be reduced toone or increased to three or more. The image sensor(s) may be relocatedto the underside of head 5 and be oriented forwardly leftward fromsewing needle 7 or may be placed on sewing machine bed 2, or any otherlocations that are capable of capturing images of sewing needle 7.

The images captured by the two or more image sensors may be synthesizedto allow extraction of a three dimensional shape of sewing needle 7.Such configuration allows even more accurate evaluation of bending ofsewing needle 7.

Abnormalities of sewing needle 7 may be informed to the user by voicemessages, illumination or flickering of a lamp, or combination of suchapproaches instead of displaying messages on LCD 20 and ringing ofbuzzer 34.

Parameters such as various measurements of sewing needle 7, thresholdvalues and the types (thickness) of sewing needle indicated in thesecond exemplary embodiment is merely exemplary and may be modified asrequired.

The above exemplary embodiments have been described by way of a sewingmachine allowing attachment of embroidery machine 22 and thus, beingcapable of embroidering; however, the present disclosure may also beapplied to sewing machines that are not provided with embroidery machine22.

The initial shape data of sewing needle 7 which was obtained by actuallycapturing the image of the newly attached sewing needle 7 in the thirdexemplary embodiment may instead be provided as a preset data ortemplate by the manufacturer to be employed as comparative data.

While various features have been described in conjunction with theexamples outlined above, various alternatives, modifications,variations, and/or improvements of those features and/or examples may bepossible. Accordingly, the examples, as set forth above, are intended tobe illustrative. Various changes may be made without departing from thebroad spirit and scope of the underlying principles.

1. A sewing machine provided with a needle bar having a sewing needleinterchangeably attached to its lower end, comprising: an imagingelement that captures images of the sewing needle; an extractor thatextracts a shape of the sewing needle from the images of the sewingneedle captured by the imaging element; an abnormality determiner thatdetermines presence/absence of abnormalities in measurements of thesewing needle based on the shape of the sewing needle extracted by theextractor; and an abnormality alerter that alerts the presence ofabnormalities determined by the determiner.
 2. A sewing machine providedwith a needle bar having a sewing needle interchangeably attached to itslower end, comprising: an imaging element that captures images of thesewing needle; an extractor that extracts a shape of the sewing needlefrom the images of the sewing needle captured by the imaging element; astorage that pre-stores an initial shape of the sewing needle; anabnormality determiner that determines presence/absence of abnormalitiesin the shape of the sewing needle extracted by the extractor bycomparing with the initial shape pre-stored in the storage; and anabnormality alerter that alerts the presence of abnormalities determinedby the determiner.
 3. The sewing machine of claim 1, wherein theabnormality determiner determines presence/absence of a bend or abreakage in the sewing needle by evaluating an overall shape of thesewing needle.
 4. The sewing machine of claim 2, wherein the abnormalitydeterminer determines presence/absence of a bend or a breakage in thesewing needle by evaluating an overall shape of the sewing needle. 5.The sewing machine of claim 1, wherein the abnormality determinerdetermines presence/absence of a rounded tip or a broken tip in thesewing needle by evaluating a tip shape of the sewing needle.
 6. Thesewing machine of claim 2, wherein the abnormality determiner determinespresence/absence of a rounded tip or a broken tip in the sewing needleby evaluating a tip shape of the sewing needle.
 7. The sewing machine ofclaim 1, further being configured to allow interchangeable modeswitching between a utility sewing mode and an embroidery sewing mode,wherein the needle bar is configured to allow interchangeable attachmentof sewing needles of different thickness, the sewing machine furthercomprising a thickness detector that detects a thickness of sewingneedle based on the shape of the sewing needle extracted by theextractor; a thickness evaluator that, when in the embroidery sewingmode, evaluates whether or not the thickness of the sewing needledetected by the thickness detector is appropriate for embroidery sewing;and a first misuse alerter that prompts replacement of the sewing needlewhen evaluated by the thickness evaluator that the thickness of thesewing needle is inappropriate for embroidery sewing.
 8. The sewingmachine of claim 2, further being configured to allow interchangeablemode switching between a utility sewing mode and an embroidery sewingmode, wherein the needle bar is configured to allow interchangeableattachment of sewing needles of different thickness, the sewing machinefurther comprising a thickness detector that detects a thickness ofsewing needle based on the shape of the sewing needle extracted by theextractor; a thickness evaluator that, when in the embroidery sewingmode, evaluates whether or not the thickness of the sewing needledetected by the thickness detector is appropriate for embroidery sewing;and a first misuse alerter that prompts replacement of the sewing needlewhen evaluated by the thickness evaluator that the thickness of thesewing needle is inappropriate for embroidery sewing.
 9. The sewingmachine of claim 1, wherein the needle bar allows interchangeableattachment of sewing needles of different thickness, the sewing machinefurther comprising a specifier that allows specification of a type or athickness of a workpiece cloth to be sewn, a thickness detector thatdetects a thickness of sewing needle based on the shape of the sewingneedle extracted by the extractor, a conformity evaluator that evaluateswhether or not the thickness of the sewing needle detected by thethickness detector conforms to the type or the thickness of theworkpiece cloth specified by the specifier; and a second misuse alerterthat prompts replacement of the sewing needle when evaluated by theconformity evaluator that the thickness of the sewing needle does notconform to the type or the thickness of the workpiece cloth.
 10. Thesewing machine of claim 2, wherein the needle bar allows interchangeableattachment of sewing needles of different thickness, the sewing machinefurther comprising a specifier that allows specification of a type or athickness of a workpiece cloth to be sewn, a thickness detector thatdetects a thickness of sewing needle based on the shape of the sewingneedle extracted by the extractor, a conformity evaluator that evaluateswhether or not the thickness of the sewing needle detected by thethickness detector conforms to the type or the thickness of theworkpiece cloth specified by the specifier; and a second misuse alerterthat prompts replacement of the sewing needle when evaluated by theconformity evaluator that the thickness of the sewing needle does notconform to the type or the thickness of the workpiece cloth.
 11. Thesewing machine of claim 1, wherein the imaging element is provided at aplurality of different locations of the sewing machine.
 12. The sewingmachine of claim 2, wherein the imaging element is provided at aplurality of different locations of the sewing machine.
 13. The sewingmachine of claim 1, wherein the imaging element comprises acomplimentary metal oxide semiconductor image sensor or a charge coupleddevice image sensor.
 14. The sewing machine of claim 2, wherein theimaging element comprises a complimentary metal oxide semiconductorimage sensor or a charge coupled device image sensor.
 15. The sewingmachine of claim 1, further comprising a liquid crystal display providedon a front face of the sewing machine, wherein the abnormality alerterissues alerts through display of message information on the liquidcrystal display.
 16. The sewing machine of claim 2, further comprising aliquid crystal display provided on a front face of the sewing machine,wherein the abnormality alerter issues alerts through display of messageinformation on the liquid crystal display.
 17. A computer readablemedium storing a needle status evaluation program that automaticallyevaluates wear of a sewing needle for use in a sewing machine providedwith a needle bar having a sewing needle interchangeably attached to itslower end, the needle status evaluation program stored in the computerreadable medium, comprising: instructions for capturing images of thesewing needle with an imaging element; instructions for extracting ashape of the sewing needle from the images of the sewing needlecaptured; instructions for determining presence/absence of abnormalitiesin measurements of the sewing needle based on the shape of the sewingneedle extracted; and instructions for alerting the presence ofabnormalities determined.
 18. The medium of claim 17, for use in thesewing machine further configured to allow interchangeable modeswitching between a utility sewing mode and an embroidery sewing mode,and the needle bar is configured to allow interchangeable attachment ofsewing needles of different thickness, the needle status evaluationprogram further comprising instructions for detecting a thickness ofsewing needle based on the shape of the sewing needle extracted,instructions for evaluating, when in the embroidery sewing mode, whetheror not the thickness of the sewing needle detected is appropriate forembroidery sewing, and instructions for prompting replacement of thesewing needle when evaluated that the thickness of the sewing needle isinappropriate for embroidery sewing.
 19. The medium of claim 17, for usein the sewing machine, wherein the needle bar is configured to allowinterchangeable attachment of sewing needles of different thickness, theneedle status evaluation program further comprising instructions forspecifying a type or a thickness of a workpiece cloth to be sewn,instructions for detecting a thickness of sewing needle based on theshape of the sewing needle extracted, instructions for evaluatingwhether or not the thickness of the sewing needle detected conforms tothe type or the thickness of the workpiece cloth specified; andinstructions for prompting replacement of the sewing needle whenevaluated that the thickness of the sewing needle does not conform tothe type or the thickness of the workpiece cloth.